If it was balanced bridged, the balanced input impedance would be double the single ended. It's not and that is odd. The other numbers no one can really dispute until they measure them, the input impedance should be something one can rationalize. It's odd, that's why I brought it up.
Glad you are enjoying them, very compact design. How many watts do you believe you are running them at? Any idea what the input voltage is to the amplifier at your usual listening volume? They specify distortion at a much lower power than they are rated, I would assume that is because at full tilt the numbers are (considerably?) higher.